Facebook is getting into the Craigslist business. The world’s most populated social network recently announced a new feature called Marketplace, which allows Facebook users to buy and sell items for other users nearby. At launch Marketplace will be a mobile-only feature for Android and iOS, and only in the U.S., U.K., Australia, and New Zealand.

Facebook says it will not be facilitating payment or delivery for Marketplace items. That’s left up to buyers and sellers who can work out the deals over Facebook Messenger or, if they share contact information, a phone call.

Marketplace will be similar to using Craigslist: you post an item, buyers contact you, and you work out the details privately. Facebook will not be taking a cut of any sales you make via Marketplace.

The company says it decided to create Marketplace because it noticed that more than 450 million people around the world visit Facebook groups dedicated to buying and selling every month. That’s a lot of activity the company wanted to continue and so Marketplace was born.

The story behind the story: For years, Facebook has been figuring out ways to learn more about its users’ buying history and patterns. One of the earliest examples was Facebook’s Beacon program where purchases on sites like GameFly andOverstock.com would be posted to Facebook for your friends to see. We won’t rehash why Beacon failed, but you can read about it here. The important thing is that with a lot of buying and selling activity on Facebook the company can use that information to more precisely target their advertising to you.

Your market place

When Marketplace rolls out to you, you’ll see a new icon in the Facebook mobile app that kind of looks like a window with a shop awning over it. The Marketplace landing page shows a listing of items for sale near you. Each item will have a large photo with its price underneath.

Tap an item to dive deeper and find out who the seller is, where they are, and to make an offer or message the seller with questions.

If that first page of items for sale near you doesn’t catch your fancy there’s a search bar at the top. From there you can search for specific items and then filter them by location, category, and price. There’s also a category browsing feature where you can, say, check out all the items near you under Housewares. Facebook says you can also change the location settings—presumably to expand the region where you’re looking for items.

Marketplace also has a Your Items section where you can save items you’re thinking about buying, look at the items you’ve sold, as well as get a message history for every Marketplace-related discussion.

Even though Facebook is moving in with its own Marketplace offering, all those buy and sell “yardsale” groups you’re already using will remain intact. In fact, the new Marketplace feature will allow you to post that old typewriter to any buy/sell group you want, as well as Marketplace.

If you don’t see the new feature yet it should roll out over the next few days. Facebook says Marketplace will hit the desktop version of Facebook in the coming months.